Air-sealed joint for rotary incinerator drums



A5 Sheets-Sheet 1 April 23 1935@ A. cHRlsTl-:NSEN

AIR SEALED JOINT FOR ROTARY INCINERATOR DRUMS Fled Nov. 5, 1932 Fg. 10 I April 23, 1935. A. cHRlsTENsEN AIR SEALED JOINT FOR ROTARY INOINERATOR DRUMS Filed Nov. 5, 1932 5 Sheets-Sheet 2 lIL/ April 23, 1935. A. cHRlsTENsEN AIR SEALED JOINT FOR ROTARY INOINERATOR DRUMS Filed Nov. 5, 1932l 5 Sheets-Sheet 5 April 23, 1935. A. cHRlsTx-:NSEN 1,993,492

AIR SEALD JOINT FOR ROTARY NCINERATOR DRUMS Filed NOV. 5, 1952 5 Sheets-Sheet 4 /A/ Vf/v Tof: IS7/vae Cyr/@fanny April 23, 1935. A. cHRlsTENsl-:N 1,998,492

AIR SEALED JOINT FOR ROTARY NCINERTOR DRUMS Filed Nov. 5, 1932 5 Sheets-Sheet 5 5%. g 57mm Patented Apr. 23, 1935 Price en, Copen, D

Application November 5, 1932, Serial No. 641,4@4 In Great Britain May 25, 1932 o The invention relates to the construction ofl the joints between a rotary-furnace drum and the adjacent stationary parts of a furnace for heat-treatment of material yof any nature, especially for combustion of town refuse and similar waste products. The joints between such, partly movable and partly stationary, furnace parts are exposed to considerable wear and tear, and have to satisfy important conditions, if the furnace is to work correctly. In order to avoid unnecessary friction, and in order to compensate for variations in length due to the unavoid- Y able 'changes in temperature, relatively wide joints must always be left open between the moving drlmi and the stationary parts of the furnace. It is now necessary, on. the one hand, to tighten these joints against thev penetration of solid substances, for instance ash or other fine particles of refuse and, on the other hand, to prevent the escape, through the joints, of gases or ill-smelling vapours from the interior of the furnace, or the entrance of air into the furnace, whereby the combustion process would become uncontrollable and would be disturbed. The

' joints between a rotary drum and the xed furnace parts, at the entrance end as well as at `the discharge end of the drum, will be exposed to an especially heavy mechanical wear, as the material accumulates at these points to a certain extent, and a considerable friction will therefore be produced on account of the rotary motion.

Finally the transition points concerned are always situated at the hot parts of the furnaceand are very seriously attacked by hot slag and the like.

According, to the invention, the points of transition are now to be constructed in such a manner that the said. drawbacks will .be almost entirely avoided, and the resulting injuries reduced to aum. In order to prevent, according to the invention, any leakage of solid particles at the transition between the stationary furnace chamber and the rotary drum, the end of the said chamber next to the rotary drum is tted, at its'bottom part, with an easily exchangeable, suitably metallic, body in continuation Aof the fe grate, which body extends some distance into the rotary drum and, at theend facing the drum, supports an exchangeable packing plate, the packing edge .of which 'ts against the inner surface of the rotary drum. By means of this body the joint between the rotary drum and the stationary part of the furnace will be covered at the point where the material slides over the joint. and at the same time the entrance (Cl. 11b-B1) oi material from the drum into the joint will be prevented by the packing plate provided. By constructing the body and the packing plate as easily exchangeable parts, due consideration is given to the fact that these parts, as mentioned s above,are exposed to a particularly intense wear, especially because the rotary drum is generally less inclined than the Ifurnace grate in front thereof, so that the material entering the drum may easily accumulate there, whereby the wear w at the points of transition will be increased.

In order to increase the resistive power of the metallic body covering thev joint according to the invention the same is constructed as a hollow body tted with the necessary openings for in- 15 y side cooling by means of air,v water or the like. In this manner it is always possible, by suitable regulation of the cooling medium, to maintain at a certain maximum temperature the body projecting into the drum, .whereby the life of the 20 said body will be increased considerably. In order also to cool the packing plate, which similarly very highly exposed, a free space is left between the hollow body and the packing plate, which space communicates with the interior of the hollow body by way of suitable openings vaiiordiirig passage for the cooling medium. If air for instance is used as the cooling medium, the interior of the hollow body can in very simple manner be connected to the space below the furnace grate, so that a part o1' the undergrate blast can pass from the said space into thev hollow body and from there into the cavity between the said body fand the packing plate. The air thus used for cooling may then enter into the rotary -drum by way of openings in the packing plate, or may be directed to the re in the stationary part of the furnace by A way of special ducts.

Also the side walls of the ixed furnace part in front of the rotarydrum are considerably exposed to from the hot material sliding down. In order also to protect this part of the walls and, at the saine time, to prevent the passage of solid particles through the joint, suitably cooled bodies are also provided at the side walls in front of the rotary drum, which bodies similar' ly project somewhat into the drum.. These lateral hollow bodies may then be connected mutually and to the rst mentioned hollow body by means of openings, so that a continuous ow of cooling medium passes through all of the hollow bodies. Even when the greatest care is used, however, the cooled furnacefparts may gradually be destroyed, and especially the packing plate at the front end of the stationary furnace part will be very severely Worn by the motion of the rotary drum and the material contained therein, so that from time to time an exchange of this member will be required. In order to facilitate and cheapen this renewal, the packing plate according to the invention is composed of individual segmental parts, so that at any time only a few of these mutually similar parts have to be exchanged.

The rotary drums of the furnaces concerned must always be fitted with a refractory lining, which must be capable of resisting, on the one hand, the mechanical inuences and, on the other hand, above all the thermal effects. While in the greater part of the rotary drum the mechanical attack is not very considerable, the same will be very serious at the point where the lining comes opposite the packing plate. There the ne, and under certain circumstances very hard, parts of the material will be inclined to enter into the narrow fissure between the packing plate and the lining, so thatV jammings will occur here, whereby a very great friction will be produced between the jammed particles of material and the lining. By this friction the lining at these points will be very considerably attacked and worn away. In order therefore to make this part of the furnace especially resistive according to the invention, the lining at the pointA nace chamber, which frame concentrically en` circles, at a certain distance therefrom, they front end of the rotary drum, a stuiilng box-like packing device being inserted between the front face of the said frame and an annular disk attached to the rotary drum.

The stuffing box-like packing is formed by the provision, between the iixed annular frame and the annular disk on the rotary drum, of a cylindrical ring concentric to the rotary drum and 'at some distance therefrom, which ring cannot rotate, but can slide somewhat in the direction of the cylinder axis, and which by means of the pressure exerted by a plate spring or the like effects tightness, on thev one hand by means of a packing attached to the xd frame and, on the other hand, by means of a packing surface provided, at right angles to the axis, on the disk rotating together with the rotary drum. The packing surface may be made from metal or any packing substance, for instance leather.

As it cannot always be entirely avoided that individual solid particles of the material, in spite of the packing provided, penetrate through the packing plate and into the annular frame and thus iind their Way to the stuiling box-like packing, the bottom side of the annular frame is iitted with apertures opening into a receptacle closed in gas-tight manner. By way of these openings any solid particles having found their way through may enter into the gas-tight receptacle, whence they may be removed from time to time by opening of a gas-tight valve. In order to discharge into the gas-tight receptacle by Way of the openings thematerial which has penetrated into the annular frame, Scrapers are provided on the drum, which scrapers push the material towards the openings when the drum is rotating.

According to the invention still further means are p vided in order to avoid with certainty the entran e of solid particles into the gas-tight packing. For this purpose suitable attachments are provided between the annular frame and the stuiling box-like packing, which attachments by suitable interengagement form a labyrinth-like path and, thereby, eiciently prevent the passage of solid particles to the gas-tight packing. Any impurities still entering may be removed by way of openings provided at the bottom part of the cylindrical ring.

As already mentioned the outlet end of the rotary drum is similarly exposed to considerable mechanical and thermal attacks, so that here too the rotary drum may easily be damaged. In order to reduce these injuries to a minimum, the discharge end of the rotary drum is fitted with a cooling jacket consisting of a cylindrical part and a frame-like part protecting the face of the drum end. According to the invention an easily exchangeable metallic hollow body is used for this purpose, the said body being fitted with suitable inlet and outlet openings affording passage for a cooling medium. By the provision of the cooling jacket the temperature of the discharge end is greatly reduced, so that injurious effects Y injured, the same may easily be exchanged and be replaced by a new jacket, without any lengthy derangement of service. In order even then to reduce to a minimum the cost of the repair and the duration of the derangement of service, the cooling jacket according to the invention consists of a greater number of segmental parts, which then may be exchanged one at a time. In order to give theindividual segmental parts of the cooling jacket an opportunity to expand on account of heat, and to attain also a lateral cooling of the individual parts, the segmental parts-are suitably disposed at some distance from one another.

As the attachment of the cooling jacket directly on to the rotary drum is still a relatively diilicult process, the cooling jacket according to the inventionis covered, in its turn,'by easily exchangeable protective plates. Hereby the advantage is attainedfthat the cooling jacket itself is not exposed to injuries, but only the protective plates. which in the easiest imaginable manner are attached to the metallic cooling jackets by meansI of screws. l

The protective plates covering the cooling jacket are cup-shaped, in such a manner that hollow spaces or cavities are formed between the protective plates and the cooling jacket, which cavities by way of openings communicate with theinterior of the cooling jacket. In this manner the protective plates as well as `the cooling jacket can be traversed by the cooling medium, and be protected against excessive heating. Furthermore, the protective plates consist suitably of individual parts disposed at some distance from one another, so that always only small elements have to be exchanged, and no stresses likely to cause any premature destruction will occur inside of the protective plates.

Water, is used, means for leading the Water away after thev same has effectedthe cooling must naturally be provided in a different manner.

Correspondingly if the cooling jacket is not fitted with protective plates, the segmental parts of the cooling jacket are-made without side walls.

In the drawings various constructions of the invention are illustrated by way of example. Fig. A1 shows a vertical longitudinal section at the point of transition from the stationary fur- 1.

nace chamber to the inlet end of the rotary drum `with a packing, in accordance with the invention,

against the entrance of solid particles into the joint and with a deviceproviding tightness against leakage of gas. Fig. 2 shows a vertical crosssection along the line II-II in Fig. 1. Fig. 3

shows, on a larger scale, a cross-section of the side wall'of the furnace chamber along the line )1I-III in Fig. 1. Fig. 4a corresponding section of the side wall along the line IV-IV of Fig. 1.

Fig. 5 shows a longitudinal section along the lineA V--V of Fig. 4, while Fig. 6, to a larger scale, reproduces the lower packing device according to Fig. 1. Fig. 7 shows a vertical longitudinal section of the outlet end of the rotary drum. Fig. 8 represents a front elevation of a portion of the discharge end of the rotary drum, illustrating a provided, and this drum consists of an outer mantle 4 with insulation 5 and an inner refractory lining 6. Between the xed furnace chamber I and the rotary drum- 3 'the joint 1 is formed. The rear wall 8 of the furnace chamberl is formed, at the bottom, by a metallic hollow body l, which projects some distance into the rotary drum 3. At the hollow body 9, which as shown, is attached by bolts to the wall of the furnace chamber so as to be rea detachable, a packing plate I is attached, similarly in easily detachable manner, which plate, asshown by Fig. 2, consists of individual segmental parts' I I. The bottom part-of the packing plate I0 is bent towards the inner faceoof the rotary drum, and nts Aagainst the inner periphery thereof. The part of the rotary drum which during. the motion of the drum passes along the packing plate Il, is lined with carborundum blocks I2. 'I'he hollow body 9 is formed as an air chamber, and

7 communicates by way of openings I3 with the part I4 'of the furnace chamber below the grate 2, .by way of which'chamber the air for combustion is'introduced. ,The air. chamber 9 is'` further provided withv openings I and I B, through which the air can enter into the interior of the for the air.

cooled by the air jets passing through. In order` 4to carry away the 'cooling air from the packing plate, the latter also is provided with openingsV I8 Also the side walls ofthe furnace chamber I are fitted with corresponding air chambers at the place where the material slides .along the same, above the air chamber 9. Figs. 3 to 5 show the arrangement of thelchambers, in longitudinal and transverse section. 'I'he air chamber I9 situated inside of the furnace chamber is formed by a plate 20 situated in front@ thereof, which is tted with ribs 2I for increasing the cooling surface on the side facing the interior of the air chamber. \In continuationV of the chamber I9 a further air chamber 22 projecting into the rotary drum 3 is'formed, which chamber is covered Vwith a similarly ribbed plate 23, and the outer limiting wall 24 of which ts the inner periphery of the rotary drum. In the corner spaces left between the air chambers I9 and 22, further air spaces 25 and 26 are formed, the arrangement and interconnection of which may be seen from Fig. 5.

The air chambers I9, 22, 25 and 26 are connected mutually as well as with the chamber 9 by suitable openings for thepassage of cooling air. The attachment of all the metallic parts belonging to the air chambers is effected in the simplest possible manner by means of screws, so that at any time an exchange of the individual parts will be possible without any diiculty. The outer walls of the lateral cooling chambers are similarly provided with openings 21 for the discharge of the cooling air into the interior of the rotary drum. v

The operation of the cooling chambers appears clearly from the drawings. 'I'he material to be combusted slides along the cooling chamber 9 into the rotary drum, so that the most exposed part of the transition from the furnace chamber to the rotary drum will be formed by the ex'- changeable cooling chamber. This part in connection with the packing plate I0 covers at the same time the joint 1 eici'ently against any solid particles falling through, the lateral cooling chambers, besides their protection of the brickwork, forming similarly a cover for the joint up `to the highest level to which the 'material will reach at this point. 'Ihe metallic part of the cooling chambers may suitably be made from cast iron.

In order to tighten the joint 1 against the escape of combustion gases, or the entrance of surplus air from the outside, a special packing is provided according to the invention, the constructional details of which appear plainly from Fig. 6. Concentrically to the inlet end of the rotary drum 3, and at some distance therefrom, `a stationary cast-iron frame 2l is attached in gastight manner to the rear wall 3 of the furnace chamber I. 0n the front face of the frame 23 a channel iron 29 is provided, which in a ring produced .by suitable mea'ns supports a packing 30 adapted to produce tightness. c

On the mantle 4 of the rotary drum 3 an angle 3| is provided, whichf itself carries an annular packing ring 32. Between the disk 32 and the frame` 28 andconcentrically to the rotary drum 3, a cylindrical ring 33 is supported t' some distance from the rotary drum in such a manner that it cannot move-in the direction of the rotation of the drum, while a certain mobility in the direction of the ldrum axis is permissible. The ring 33 is supported on the packing 30 and carries on its front side', by means of an angle iron' 34 an element 36 fitted with a packing surface 35, which element with its packing surface slides on the packing ring 32. The rotary motion of the ring'33 is prevented by angular brackets 38 attached to the ring 33 and engaging-fin pawllike manner the brackets 31 attached to the frame 28. In the .direction of the axis of the rotary drum the ring 33 is freely movable, a platefspring 39 insertedbetween the frame 28 andthe member 34 eiecting the requisite pressure .of the ring 33 with its packing surface 35 against the packing ring 32.

In order to be able to remove any solid constituents that in spite of the packing plate l0 may have penetrated into the lower packing device, openings 40 are provided in the bottom part of the frame 28, which openings lead to a vessel 4|, closed in gas-tight manner towards the outside and terminating in a flap 42. Further, the bottom surface of the cylindrical ring 33 is provided with openings 43, which similarly serve to remove any solid particles that may have entered. In order to prevent, as far as possible, the entrance of these particles into the packing device itself, there is further inserted, in front thereof, a labyrinth-like device formed by interlocking angles and plates 44. Arrows in Fig. 6 showy the path that may be followed by any solid particles entering from the interior of the rotary drum. In order to remove, emciently by way of the apertures 4D, the particles deposited in the bottom part of the frame 28, the outer periphery of the drum 3 is tted at this point with Scrapers 45, which push the solid particles towards the apertures 40.

Fig. 6 shows plainly how eiriciently a gas-tight joint is attained, by the arrangement according to the invention, at the point of transition from the furnace chamber to the rotary drum. By the movable attachment of the cylindrical ring 33, which effects the tightness, care is taken to maintain the tightness in spite of any displacement of the rotary drum owing to external influences or to the action of heat.

Figs. '1 to 11, finally, show also the discharge end of the rotary drum .with cooling chambers provided in accordance with the invention. At this end the rotary drum 3 is tted with a cooling jacket 46, which forms an annular chamber 41 encircling the end of the rotary drum. By way of openings 48, which can be adjusted by anannular slide valve, the chamber 41 communicates with the outer air, so thatvcooling air can enter here. For the purpose of protecting the end face of the drum, an annular frame-like body 49 is attached by means of screws 50, in easily exchangeable manner, partly to the drum itself and partly to the mantle 46 of the cooling chamber 41, the interior of the said body communicating by way of an opening 5|, with the chamber 41 and being provided with outlet openings 52 for the cooling air. By the suction prevailing in the adjoining' chimney 59, the outer air is directed through the openings 48 into the chamber 41, and from there into the interior of the body 49, whence the air escapes to the chimney by Way of the openings 52. -According to Fig. 9, the protective device 49 for the end face of the drum may be :formed by individual segmental parts 49', which for the purpose of compensating for thermal expansions are placed at some distance from one another so as to form joints 50'. If no further protection of the member 49 be provided, the individual segmental parts 49 are closed on the sides, so that the cooling air can escape only by Way of the openings 52.

A further protection of this part of the furnace is provided by shell-shaped plates 53, 51 'and 58, which in easily exchangeable manner are attached to the mantle 4B and the member 49 respectively. Owing to the arched shape, cavities 54, 55, 56 are left open between the individual parts, which cavities, by way of the openings 52, communicate with the cooling chamber 41 and, respectively, the interior of the said parts. The

l By the provision of small individual protective i parts of standard shape at the highly exposed outlet end of the rotary drum, the advantage is attained that any injury to this part of the furnace can be repaired in a most simple and l cheap manner, without any lengthy derangements of service being caused thereby. The introduction of the cooling air into the furnace l parts concerned, at the entrance end as well as ,l atvthe outlet end of the rotary drum, may either 5 be effected solely by the chimney draft or by special fan devices.

Having thus described my invention, what I claim is:-

1. In a furnace having a stationary chamber, a f grate within saidA chamber, and a rotary drum adjacent to said chamber, an air-sealed joint between the wall of said chamber and said rotary drum and comprising a body removably secured to the lower portion of the chamber wall, said body forming a continuation of the furnace grate and extending into the rotary drum, and a removable packing plate c'arried by said body and i having its periphery in contact with the inner l Vsurface of the drum. l

2. In a furnace having a stationary chamber, a l grate within said chamber, and a rotary drum adjacent to said chamber, an air-sealed joint be- 1 tween the wall of said chamber and said rotary drum and comprising a hollow body removably secured to the lower portion of the chamber Wall, said body being provided with openings in its walls for the passage of a cooling fluid and extending into the rotary drum, and a removable packing plate carried by said body and having its periphery in contact with the inner surface of the drum.

3. In a furnace having a stationary chamber, a grate within said chamber, and a rotary drum adjacent to said chamber, an air-sealed joint between the wall of said chamber and said rotary drum and comprising a hollowbody removably secured to the lower portion of the chamber wall, said body being provided with openings in its walls for the passage of a cooling fluid and extending into the rotary drum, and aV removable packing plate carried by said body and having its periphery in contact with the inner surface of the drum, said packing plate being spaced from the hollow body and provided with openings communicating with the interior of the hollow body.

4. In a furnace having a stationary chamber, a grate within said chamber, and a rotary drum adjacent to said chamber, an air-sealed joint between the wall of said chamber and said rotary j drum and comprising a body removably secured to the lower portion of the chamber wall, saidj body forming a continuation of the furnace grate and extending into the rotary drum, a removable packing plate carried by said body and having its periphery in contact with the inner surface of the drum, an air-cooled member disposed on the side walls of the chamber adjacent to the rotary drinn, said members extending into the drum.

5. In a furnace having a stationary chamber, a grate within said chamber, and a rotary drum adjacent to said chamber, an air-sealed joint between the wall of said chamber and said rotary drum and comprising a body removably secured to the lower portion of the chamber wall, said body forming a continuation of the furnace grate and extending into the rotary drum, and a removable packing plate carried by said body and.

having its periphery in contact with the inner surface of the drum, said packing plate comprising a plurality ofv individual removable segmental members.

6. In a furnace having a stationary chamber, a grate within said chamber, and a rotary drum adjacent to said chamber, an air-sealed joint between the wall of said chamber and Isaid rotary drum and comprising a body removably secured to the lower portion of the chamber wall, said body forming a continuation of the furnace grate and extending into the rotary drum, said rotary drum having a ring of abrasive material forming a part of its lining, and a removable packing plate carried by said body and having its periphery in contact with the inner surface of said .abrasive ring.

7. In a furnace having a stationary chamber, a grate within said chamber, and a rotary drum adjacent to said chamber, an air-sealed joint between the wall of said chamber and said rotary drum and comprising a body removably Isecured to the, lower portion of the chamber wall, said body forming a continuation of the furnace grate and extending into the rotary drum, a removable packing plate carried by said body and having its periphery in contact with the inner surface of the drum, an annular ring secured to the rotary drum at the exterior thereof, an annular frame hermetically secured to the wall of said chamber and encircling the end of the rotary drum in spaced relation thereto, and a stung box packing device disposed between said frame and said ring.

8. In a furnace having a stationary chamber, a grate within said chamber, and a rotary drum adjacent to'said`chamber, an air-sealed joint between the wall of said chamber and said rotary drum and comprising a body removably secured to the lower portion of the chamber wall, said body forming a continuation of the furnace grate and extending into the rotary drum, a removable packing plate carried by said body and having its periphery in contactwith the inner surface of the drum, an annular ring secured tothe rotary drum at the exterior thereof, an annular frame hermetically secured to the wall of said chamber and encircling the end of the rotary drum in spaced relation thereto, a ring of packing material carried by said frame, a cylindrical ring disposed in concentric relation to the rotary drum between said frame and said annular ring, said cylindrical ring being spaced from the drum and movable in the direction of its axis, and a spring in engagement with said cylindrical ring for retaining it in contact with said annular ring.

9. In a furnace having a stationary chamber, a grate within said chamber, and a rotary drum adjacent to said chamber, an air-sealed joint between the wall of said chamber and said rotary drum and comprising a body removably secured to the lower portion of the chamber wall, said body forming a continuation of the furnace grate and extending into the rotary drum, a removable packing plate carried by said body and having its periphery in contact with the inner surface of the drum, an annular ring secured to the rotary drum at the exterior thereof, an annular frame hermetically secured to the wall of said chamber and encircling the end of the rotary drum in spaced relation thereto, va stuffing box packing device disposed between said frame and said ring, a hermetically'fsealed container disposed below the joints between the chamber and drum, and said annular frame being provided with openings in the lowerportion thereof in communication with said. container.

' 10. In a furnace having a stationary chamber, a grate within-said chamber, and a rotary drum adjacent to said chamber, an air-sealed joint between the wall of said chamber and said rotary drum and -comprising va body removably secured to the lower'portion of the chamber wall, said body forming a continuation of the furnace grate and extending into the rotary drum, a removable packing plate carried by said body and having its periphery in contact with the inner surface of thedrum, an annular ring secured to the rotary drum at the exterior thereof, an annular frame hermetically secured to the `wall of said chamber and encircling the end of the rotary drum in spaced relation thereto, a stufng box packing device disposed between said frame and said ring, a hermetically sealed container disposed below the joints between the chamber and drum, said annular frame being provided with openings in the inner portion thereof in communication with lsaid container, and scrapers secured to the exterior of said drum for conveying material toward said openings.

11. In a furnace having a stationary chamber, a grate within said chamber, and a rotary drum adjacent to said chamber, an air-sealed joint between the wall of said chamber and said rotary drum and comprising -a body removably secured to the lower portion of lthevchamber wall, said body forming a continuation of the furnace grate and extending into the rotary drum, a removable packing plate carried by saidbody and having its periphery in contact with the inner surface of the drum, an annular ring secured to the rotary drum at the exterior thereof, an annular frame hermetically secured to the wall of said chamber and encircling the end of the rotary drum in spaced relation thereto, a stufng box packing device disposed between said frame and said ring, and members disposed between said frame and said packing device and forming baflles for prei venting the passage stuffing box.

12. In a furnace having a stationary chamber,

of solid particles into the a grate within said chamber, and a rotary drum adjacent to said chamber, an air-sealed joint between the wall of said chamber and said rotary drum and comprising a body removably secured to the lower portion of the chamber wall, said body forming a continuation of the furnace grate and extending into the rotary drum, a removable f packingplate carried by said body and having its cylindrical ring being spaced from the drum and movable in the direction of its axis, and a spring in engagement with said cylindrical ring for retaining it in contact with said annular ring, said cylindrical ring being perforated at its lower portion thereby to permit removal of material therefrom.

13. In a furnace having a stationary chamber, a grate within said chamber, and a rotary drum adjacent to said chamber, an air-sealed joint between the wall of said chamber and said rotary drum and comprising a body removably secured to the lower portion of the chamber wall, said body forming a continuation of the furnace grate and extending into the rotary drum, a removable packing plate carried by said body and having its A periphery in contact with the inner surface of the drum, said rotary drum being provided at its discharge end with a cooling jacket comprising acylindrical member 4enci'clingthe drum anda protecting frame concentric with the 'drum and disposed adjacent'trtheend of the drum.

14. In a furnace having a stationary chamber, a grate within said chamber, and a rotary drum adjacent to said chamber, an air-sealed joint between the wall of said chamber and said rotary drum and comprising a body removably secured to the lower portion of the chamber wall, said body forming a continuation of the furnace grate and extending into the rotary drum, a removable packing plate carried by said body and having its periphery in contact with the inner surface of the drum, a cooling jacket encircling said drum at its discharge end and comprising a removable metallic hollow body having inlet and outlet openings for the passage of a cooling medium and a protecting frame disposed in concentric relation with the drum adjacent to the end of said drum.

15. In a furnace having a stationary chamber, a grate within said chamber, and a rotary drum adjacent to said chamber, an air-sealed joint between the wall of said chamber and said rotary drum and comprising a body removably secured to theglower portion of the chamber wall, said body forming a continuation o f the furnace grate. and extending `into 'the rotary drmx a removable packing plate carried by said body and having its periphery in contact with the inner surface of the drum, a cooling jacket encircling the discharge end of the rotary drum and comprising' a plurality of removable segmental members, and a protecting frame disposed in concentric relation with the drum adjacent to the end of said drum.

16. In a furnace having a stationary chamber, a grate within said chamber, and a4 rotary drum adjacent to said chamber, an air-sealed joint between the .wall of said chamber and said rotary drum and comprising a body removably secured to the lower portion of the chamberwall, said body forming a continuation of the furnace grate and extending into the rotary drum, a removable packing plate carriedby said body and having its periphery in contact with the inner surface of the drum, a cooling jacket encircling the discharge end of the rotary drum and-comprising a plu-- a grate within said chamber, and a rotary drum adjacent to said chamber, an air-sealed joint between the wall of said chamber and said-rotary drum and comprising a body removably secured to the lower portion of the chamber wall, said body forming a continuation of the furnace grate and extending into the rotary drum, a removable packing plate carried by said body and having its periphery in' contact with the inner surface of the drum, said rotary drum being provided at its discharge end with a cooling jacket comprising a cylindrical member encircling the drum, a protecting frameconcentric with the drum anddisposed adjacent to the end of the drum, and removable -protecting plates enclosing said cooling jacket.

18. In a furnace having a stationary chamber,

a grate within said chamber, and a rotary drum .adjacent to said chamber, an air-sealed joint between the wall of said chamber and said rotary drum and comprising a body removably secured to the lower portion of the chamber wall, said body forming a'continuation of the furnace grate and extending into the rotary drum, a removable packing plate carried by said body and having its periphery in contact with the inner surface of the drum, said rotary drum being provided at its discharge end with a cooling jacket comprising a cylindrical member encircling-the drum, a protecting frame concentric with the drum and disposed adjacent to the end of the drum, removable protecting plates enclosing said cooling jacket, said protecting plates being provided with cavities in the sides thereof adjacent to the cooling jacket, and said cooling jacket having openings in its walls communicating with said cavities.

19. In a furnace having a stationary chamber, a grate within said chamber, and a rotary drum adjacent to said chamber, an air-sealed joint between the wall of said chamber and said rotary drum and comprising a body removably secured to the lower portion of the chamber wall, said body forming a continuation of the furnace grate and extending into the rotary drum, a removable packing plate carried by said body and having its periphery in contact with the inner surface of thev drum, said rotary drum being provided at its discharge end with a cooling jacket comprising a cylindrical member encircling the drum, a protecting frame concentric with the drum and disposed adjacent to theend of the drum, and removable protecting plates enclosing said cooling jacket, said removable plates being spaced apart.

20. In a furnace having a stationary chamber, a grate within said chamber, and a rotary drum adjacent to said chamber, an air-sealed joint between the wall of said chamber and said rotary drum and comprising a body removably secured to the lower portion of the chamber wall, said body forming a continuation of the furnace grate' uand extending into the rotary drum, a removable said protecting plates being provided with cavities'in the sides thereof adjacent to the cooling jacket, and said cooling jacket having openings in its walls communicating with said cavities, said cavities being open to the atmosphere.

AAGE CHRISTENSEN. 

